As has already been noted by John Panzer, Kevin Lawver and others, AOL is providing an OpenID URL for all AOL & AIM members. This enables a significant number of consumers with an OpenID URL. I hope this encourages greater participation amongst existing services on the web. I find that many of the services I want to try out, don't support OpenID and hence I tend not to go through the whole registration process just to see if the site offers the services I'm interested in. Greater participation by relying parties will be key for adoption and use of OpenID by the "mass market".
In the "adoption and use" department... Given that many AOL users will not realize they have an OpenID, it would be great if the help text for "what is an OpenID?" on relying party "login" screens would mention that if you have a LiveJournal or AOL account, you already have an OpenID. This isn't very inclusive so maybe there could be a link ("Do I already have an OpenID?") to a wiki page or something that could be updated as more OpenID Providers become available. This isn't that important for those who explicitly create OpenID's at OpenID providers, but is important for those consumers who have an OpenID by virtual of having an account for other services.
Tags: OpenID, AOL